Printing telegraph apparatus



Feb. 16, 1943. c, VIN

rnmwm; TELEGRAPH APPARATUS Original Filed April 25, 1938 i Sheets-Sheet 1 mvENToR CARL A. u-zvm ly/5x49 ATTORNEY Feb. 16, 1943. c. A. LEVIN 2,310,96

PRINTING TELEGRAPH APPARATUS Original Filed April 25, 1938 2 Sheets-Sheet 2 FIG. 2

INVENTOR. CARL A. LEVIN Patented Feb. 16, 1943 PRINTING TELEGRAPH Carl A. Levin, Chicago, 111., assignor to Teletype Corporation, Chicago, 111., a corporation of Delaware Original application April 25,1930, Serial No.

204,038. Divided and this application December 30, 1939, Serial No. 311,767

5 Claims. (01. 191-53) This invention relates to printing telegraph apparatus and particularly to printing telegraph apparatus in which the characters are printed from type elements carried upon the periphery of a rotatable and selectively arrestable type wheel.

This application is a division of application, Serial No. 204,038, filed April 25, 1938 by C. A. Levin, which has matured into Patent No. 2,230,463, issued February 4;l941.

An object of the invention resides in the provision, in a printing telegraph receiving unit embodying a type wheel having displaceable type elements, of instrumentalities for actuating said elements capable of extremely rapid positive operation.

Another object of the invention resides in the provision of a simplified easily assembled type wheel of the kind having displaceable type elements.

The invention features apparatus for actuating the individual type elements of a type wheel including a print hammer which is actuated by a cam follower and having a yieldable element included in the linkage interposed between the print cam and the print hammer whereby the actual printing operation is performed by the expenditure of kinetic energy of the print hammer and possibly an additional element or elements, such kinetic energy resulting in overtravel of the print hammer permitted by the yieldable element.

According to the present invention, a reciprocable printing member is provided for actuating the type'elements individually. A bail carries a follower roller which engages the periphery of a lrinting cam, the bail being biased into engagement with the cam by a tension spring. Operation of the printing member is effected'when the rinting bail cam follower roller rides down an abrupt drop in the printing cam. The distance through which the printing bail is operated by its spring is insufficient to bring the printing member into engagement with a type element.

ficient to cause a selected'type elementto' effect printing. The spring which yields and'p'errn'its the overtravel immediately retracts the printinig element to-unoperated position, thereby clearing A. spring is-interposed betweenthe printing bail the path of unoperated type elements so that the type wheel may be rotated t'o'a new position.

A'type wheel disclosed in copending application Serial Ndp'l'lj'l fi filed'May 4,- 1936, by Albert H. Reiber and also in Patent No. 2,180,360 issued November 21, 1939, to Howard L. Krum et a1. comprises'spaced slotted flanges joined by a cylindrical drum portion which is also slotted. Type'pallets slidable radially of the type wheel are mounted in the'slots in the type wheel, there being two type pallets in each slot. The shanks of the type pallets in the upper row have recesses which open downwardly" and the shanks of the type pallets in the lower row have recesses which open upwardly. A' garter spring individual to each row of type pallets is disposed in the recesses in the shanks of all of the type pallets in a row and biases the pallets to their innermost positions. A floating ring partially enters the space between the two' g'arter springs, whereby it rests upon and is supported by one of the springs and whereby it" also prevents the springs from shifting out'of the desiredposition. I

Inthe type wheel according to the present invention, the drum portion of the wheel which joints the upper' and lower flanges has a peripheral rib intermediate the upper and lower'fla'nges. The rib thus divides the'surffa'ce of the drum portion into two peripheral grooves which serve as seats for the garter springs and confine the springs in the desired position. The garter springs are thus kept in proper position without the assistanceof a floating ring.

For a complete understanding of the invention, reference may be had to the followingdetailed description to be interpreted'in the light of the accompanying drawings, wherein Fig. l is a perspective view of printing telegraph apparatus including'the type wheel and features of the printing mechanism in accordance with the present invention;

Fig. 2 isa plan view'with'portions broken away showing the overtravel printing mechanism in accordance with the present invention; and

Fig; 3 is a view partly in elevation and partly in section showing detailsof' the type pallet operating mechanism and of the type wheel, the type pallet operating mechan'ismbeing shown in elevationand the type wheel being shown in' section.

Referring now to the drawings and particularly to Fig. 1 the reference numerals l5 and H designate'generally the typing unit and keyboard transmitter unit, respectively, of a printing telegraph apparatus embodying-'the'present invention. The typing unit it is identical with that shown in Patent No. 2,247,408 issued July 1, 1941 to Albert H. Reiber and the keyboard transmitter unit H is identical with that shown in the said patent of Albert H. Reiber and is similar to that shown in copending application Serial No. 77,796 filed May 4, 1936, by Albert H. Rei-ber.

The foundation of the keyboard transmitter unit is the base casting l3 to the forward vertical wall of which is secured a slotted comb HE. A plurality of key levers 2i are pivoted within the casting 58 for rocking movement in a vertical plane and these key levers protrude from the interior of base it through the slots in comb I9. The key levers 2| are provided with keytops 22 and arranged to impart characteristic settings to permutation code bars contained within base l3 as fully disclosed in United States Patent No. 1,595,472 granted August 10, 1926, to Howard L. Krum. To the code bars are articulated lock levers pivotally supported intermediate their ends and projecting above the upper surface of base casting l9 through apertures therein. The lock levers 23 are therefore subject to permutative setting by the code bars under the control of key levers 2i.

The upwardly projecting portions of lock levers 23 cooperate individually with transmitting contact control levers 24 to determine whether or not their individual contact control levers 24 shall i be permitted to operate under the control of transmitting earns 25 carried by transmitting cam assembly sleeve 2?. The sleeve 21 'is supported by a transmitting distributor shaft 28 to which is secured continuously driven gear 29 and to which is also secured the driving element 3| of a single revolution positive drive clutch mechanism which includes the driven element 32. A compression spring 33 urges driven element 32 to engage driving element 3| and a clutch throwout lever 34 normally holds driven element 32 out of engagement with driving element 3|. throwout lever 34 is tripped by a bell crank 35 which is operated by a lever 31 articulated to a universal bail which is contained within the base casting l8 and is operated upon the depression of any key lever 25.

The principal foundation element of the typing or receiving unit is a casting which mounts on the keyboard base l8 and has a portion 4| located centrally of the base is and a portion 42 extending transversely'of the base in proximity to the rear edge thereof. Thumb screws are employed for securing the casting comprising portions 4i and 42 to the base l8 and one of these screws is indicated at 43. A secondary casting 44 extends transversely of the keyboard base It and is secured to portion 42 of the primary casting by any desired means, such as screws. The primary casting supports all of the power driven shafts, the operating cam assemblies, the selector mechanism, the printing mechanism, and the ribbon feed mechanism. The secondary casting 44 supports the platen carriage and associated mechanism, the signal bells and a set of levers by which various function are performed- The primary selector mechanism which integrates the signal combinatlons generated in the keyboard transmitter mechanism hereinbefore described, or in a remote transmitter, is indicated generally by the reference numeral 46 and is identical with the primary selector mechanism disclosed and described in considerable detail in the hereinbefore identified patent of Albert H.

Clutch Reiber No. 2,247,408. The principal elements of the selector mechanism 46 are a selector cam assembly 41, a selector magnet 48, and a sword and T lever selector assembly 49, the last mentioned assembly as well as the selector magnet being supported by a mounting plate 5| carried by the forwardly extending portion 4! of the primary casting. The selector cam assembly 41 is carried at the upper end of a vertically positioned shaft which is rotatably supported in hearing blocks 52 and 53. Friction discs are confined between end flanges of the selector cam assembly 41 and discs secured to the shaft on which the cam assembly is mounted, so that the cam assembly may rotate with the shaft or may be held against rotation. Just above the point at which it enters lower bearing block 52 the shaft has secured thereto a gear 54 which is continuously driven by an electric motor (not shown) through suitable gearing (also not shown).

The sword and T lever mechanism 49 is actuated under the joint control of selector cam assembly 41 and selector magnet 48 to interpret or integrate a series of impulses representing a signal combination preparatory to setting T levers 55 in accordance with the signal combination. Each of the T levers 56 engages one arm of a transfer bell crank 51, the other arm of which is articulated to one of the notched code discs of a code disc selector mechanism indicated generally by the reference numeral 58.

The code disc selector mechanism 58 has a circular arrangement of vertically positioned stop pins 59 which project through slots in the topmost plate of the mechanism. Stop pins 59 are biased inwardly radially of the code disc selector mechanism and near their upper ends they rest against the edges of shiftable notched code discs, as i fully disclosed in the hereinbefore identified application and patent of Albert H. Reiber, and in the patent of C. A. Levin. The notching of the code discs is such that for any permutative setting of the discs under the control of T levers 56, one and only one of the stop pins 66 finds presented to it an alignment of notches, whereupon the pin enters the alignment of notches and it upper end moves inwardly. A type wheel stop arm 6|; which is clamped to type wheel shaft 52 journaled in the code disc selector 58, is of such length that in revolving it just clears those of the stop pins 59 which are held in their outermost positions by the code discs, but finds blocking its path any pin 59 which has entered an alignment of notches in the periphery of the code discs. The type wheel shaft 62 carries a gear which is continuously driven from the electric motor, and a friction clutch assembly is interposed between the gear and shaft 52 so that the shaft may remain stationary while it driving gear is rotated continuously. Shaft 62 is thus prepared to rotate at any time and is free to rotate when any stop pin 59 which had been previously selected is moved out of the path of stop arm 6| upon the resetting of the code discs. With this arrangement shaft 52 may be arrested in any angular position in which stop arm 5| encounters a stop pin 59.

The setting of the T levers 55 according to the operation of the sword lever mechanism 49 is controlled by a pivoted transfer bail 63 which is operated by a cam 68 included in a cam assembly 61 carried by a vertically extending shaft journaled in brackets 64 and 66 at the front of the printing unit. The reference numeral 59 designates a cam follower arm which is carried by the bail and by which it is operated. The shaft which carries cam assembly 81 has driving and driven clutch elements II and I2, the latter of which is connected to the cam assembly 61 and the former of which is connected to gear I3 which meshes with a gear I4 secured to continuously rotated gear 54. The clutch comprising elements II and I2 is of the single revolution positive drive type and is tripped for engagement by lever I6 under the control of receiving selector cam assembly 41.

Cam assembly 61 includes a cam 11 which is engaged by a cam follower carried by a pivoted bail 18. Bail I8 has an arm 80, the rearmost end of which is connected by a spring 19 to a type wheel supporting frame 8| which is slidable vertically upon pins 82. At the top, frame 8| has a horizontally extending portion 83 through which type wheel shaft 62 passes and in which is rotatably held the hub 84 (Fig. 3) of a type wheel 88. Hub 84 is slidable upon type wheel shaft 62 and when bail I8 is rocked in counterclockwise direction as viewed in Fig. 1 by cam 'I'I spring I9 causes frame 8| to move upwardly and thus type wheel 86 is lifted to bring either of two rows of type pallets into printing position. The vertically extending portion of frame 8| is provided with an arm 81 which extends into an aperture in a forwardly and rearwardly slidable member 88. The aperture in slidable member 88 is stepped to provide two stops for the arm 81 carried by frame 8|. When slidable member 88 is in one position the upward movement of frame 8| is arrested by engagement of arm 81 with one of the stop surfaces when the type wheel has been elevated into position for printing from the upper row of type pallets and when the slidable member 88 is in the other position, the frame 8| is arrested when the type wheel has been elevated into position for printing from the lower row of type pallets. The movement of slidable member 88 back and forth between its two positions is controlled by the shift and unshift function mechanism of the printer as is fully disclosed in Patent No. 2,247,408 issued July 1, 1941 to Albert H. Reiber.

Printing is effected under the control of a cam 89 included in a cam assembly 9| carried by the shaft which is journaled in bearing blocks 52 and 53 and which supports the receiving selectorcam assembly 41. The shaft has secured thereto the driving element 92 of a single revolution positive drive clutch mechanism and the driven element 93 of the clutch mechanism is connected to the cam assembly 9|. Driven clutch element 93 is normally held out of engagement with driving element 92 by clutch throwout lever 94 which is operated once in each revolution of cam assembly 61 by cam 96 included therein.

Cam 89 is engaged on the periphery thereof by a follower roller 91 carried at the end of a print bail operating lever 98 which is pivoted at 99. Lever 98 has integral therewith an arm |0I which is provided near its outer end with a plurality of spring connection apertures I02. apertures I02 is adapted to receive one end of a tension spring I 83, the other end of which is supported by a spring post I04. Spring I08b'iases lever 98 in counterclockwise direction, thus urging cam follower roller 91 into engagement with- The several spring Any one-of the 7 3 is. sufficient'to reciprocate the aligned' type pallet end of type wheel shaft 82.

A print hammer operating bail I86 is pivotally supported by pivot 99- and-coa-xially mounted pivot I01. At its lower end ba-il- I08 is provided with an arm I;08 which supports adjustable abutment screw' I09 and also one end of a tension spring III. The inner end of abutment screw I09 engages-anarm I I2- of lever 98 and therearmost end of tension spring I I I is also-connected to arm I I2 of lever 98. With this arrangement, bail I05 tends to occupy extremeclockwise position with respect to'lever 98, the extremity of the position being determined by abutmentscrew I09.

Print hammer operating bail I06 has integral therewith at its upper end a lever arm I I3. At its free end lever arm II3 islooselyarticulated to a print hammer II4. Printhammer H4 extends between ribbon spools I I6 rotatably mounted upon a ribbon feed mechanismsupporting plate I I1. Print hammer H4 is provided withupper and lower arms H8 and H9, respectively, which are disposedin the same vertical plane. Lower arm 9' enters a slot in a bracket I2I carried by ribbon feed mechanism foundation plate I I1 and by means of slotted bracket IZIprint hammer I I4 is held in a vertical plane and is guided in reciprocatory motion imparted by arm 3 of bail I06. The upperarm- I I8 of print hammer I I4 is longer than the lower arm |I9 andextends across the periphery of type. wheel 88 and across the upper At its free end, arm H8 is provided with adepending portion I22 which, in turn, is provided withan arm I23 the location of which is in alignment with the foremost portion of platen. |24',.which portion is at the level where. printing occurs.

Cam 89 in its norma1 or rest position holds print bail operating lever 98 in extrem'ecloekise position in opposition to the tension of spring I03. Spring I|| holds print hammer bail I06 in extreme clockwise position with its abutment screw I09 in engagement with arm II2 of print bail operating 1ever'98'. Thus, print hammer H4 is held in retractedposition. At a predetermined time in theoperation of cam 89 a sharp dropoif is presentedto follower roller 9'! of print bail operating lever 98. When the dropoff is encountered lever 98.is rocked sharply in counterclockwise direction by spring I03. Lever 89 imparts counterclockwise movement to bail I89. through abutment screw I09. The angular distance through which lever 98 rocks as cam follower'roller '91 descends to'the'lowest or innermost point on the" periphery of cam 89 is just short of sufficient to drive print hammer I|4 positively againstithetype pallet aligned therewith. However; the-inertia of bail I06 and print hammerxl I4 causes .springI I I to yield and abutment screw I09 to move out of engagement with arm II2. Thus... printhammer I|4 overtravels or moves a greater: distance than it would if positively interconnectedwith lever 98,.the overtravel being caused bythe inertia of bail I08 and print hammerv I I4- and .b'eing' permitted by spring III.

As soon as the energy. generated by the inertia of bail I06 and print hammer. II4 has been expended, spring withdraws print hammer H4 in the direction of its retracted position until abutment screw I09 returns into engagement with arm II2 of lever 98. The remainder of the movement of print hammer II4 to its rest position is eifected'by the restoration of lever 98 to its extreme clock-wise position by cam 89. The overtr-avel in themovement of print hammer I I4 radially of type Wheel 86 to efiect printing. During the period of overtravel and restoration, the free end of arm II8 of print hammer H4 is presented between the type pallets adjacent to that which is being operated so that the type wheel 66 could not be rotated even if permitted to do so by arm BI, due to the fact that interference between arm I23 of print hammer H4 and an adjacent unoperated type pallet would occur. Spring IiI withdraws print hammer II4 from a position of interference with unoperated type pallets much more rapidly than it could be withdrawn if positively connected to print hammer bail operating lever 98. Thus, with the arrangement hereinbefore described, the print hammer I I 4 is projected and retracted in the shortest possible interval of time so that more time may be allowed for the rotation of type wheel 86 to the position corresponding to the next selection.

Reference should now be had to Figs. 2 and 3 in which is shown the type pallet operating mechanism according to the present invention, which is a modification of that described with reference to Fig. 1. Reference numeral I26 designates a print hammer operating lever which is in the form of a bell crank lever and comprises arms I21 and I28. The free end of arm I21 supports a cam follower roller I29 which engages the periphery of a print controlling cam I3I which may be identical with the print controlling cam 89 in Fig. 1 and may operate in exactly the same manner and according to the same timing. The pivotal mounting for lever I26 (not shown) may be identical with pivot rod 99 of lever 98 in Fig. 1. The location of the pivotal mounting for lever I26 is indicated by the screw I32. Arm I28 of lever I26 is provided with an arcuate slot I33, the center of the arc of which coincides with the pivotal axis of lever I23. A clamping screw I34 extends through slot I33 and threadedly engages one arm I36 of a bell crank I31. Bell crank I31 is pivoted coaxially with lever I23, the screw I32 serving as the upper pivot for the bell crank. Arm I36 of bell crank I31 rests upon arm I28 of bell crank I26 and screw I34 clamps the two arms rigidly together, the slot I33 affording provision for angular adjustment of bell crank I31 relative to lever I26. Bell crank I31 has an arm I38 disposed in a horizontal plane considerably above that in which arm I36 is located and specifically in the plane of the type wheel. A vertica1 bar I39 integral with arms I 33 and I38 interconnects the two arms and completes the bell crank I31. Upper arm I33 of hell crank I31 is provided with a plurality of apertures I4I any one of which may receive one end of a tension spring I42, the other end of which is connected to a stationary bracket I43. Spring I42 biases bell crank I31 in counterclockwise direction and thus urges cam follower roller I29 into engagement with the periphery of cam I3I. Spring I42 furnishes the power for actuating the type pallets, and by shifting the foremost end of spring i42 from one to another of the holes I4I, the tension of the spring may be increased or decreased as desired.

At its free end, arm I33 of bell crank I31 carries a screw I44 which supports a spring post 146. A print hammer or type pallet operating member I41 is provided in its foremost end with an open ended slot I48 which fits over screw I44, the foremost end of print hammer I41 resting upon arm I33 of bell crank I31. Print hammer I41 is guided and further supported for reciprocational movement by a bracket I49 which may.

L. Krum et a1.

be similar to bracket I 2| in Fig. 1. A tension spring I5I which has one end engaging print hammer I41 and the other end engaging spring post I46 urges print hammer I41 to extreme position of retraction which may be determined by engagement of the closed end of slot I48 with screw I44 or by engagement of a laterally extending projection I32 of print hammer I41 with adjustable eccentric I53 secured to plate II1 which supports ribbon spools I I6. Print hammer I41 is provided with a shoulder I54 which may come into engagement with adjustable eccentric I53 when the print hammer is reciprocated rearwardly of the printing telegraph receiving unit to limit the operating stroke of the print hammer and prevent excessive reciprocation of the type pallets.

In Fig. 2 the printing mechanism is shown in the condition which exists just before a printing operation, bail I23 and bell crank I 31 being in extreme clockwise position and the free end of print hammer I41 being retracted well back from the type pallets. As cam follower roller I29 traverses the dropoff in cam I3I, lever I26 and bell crank I31 are rocked by spring I42 to extreme counterclockwise position, the movement to this position being relatively sharp. Screw I44 engages the inner or closed end of slot I48 in print hammer I41 and positively reciprocates the print hammer toward the inner end of the type pallet which is aligned therewith. The positive movement of print hammer I41 by bell crank I31 ceases when cam follower roller I29 engages the innermost portion of the periphery of cam I3I and the termination of the positive movement occurs just before the free end of print hammer I41 engages the aligned type pallet. The inertia of print hammer I 41 causes the print hammer to continue to move rearwardly of the printing unit after bell crank I31 has been arrested, the inner end of slot I48 drawing away from screw I44 and spring I5I yielding to permit the additional or overtravel movement of the print hammer.

The overtravel is sufficient to drive the type pallet radially of the type wheel to effect printing, the free end of the print hammer I41 moving into the space between the type pallets on either side of the one actuated. As soon as the kinetic energy of print hammer I41 has been dissipated, spring I5I retracts the print hammer until the inner end of slot I48 engages screw I 44 or until projection I52 engages eccentric I53, and such retraction is sufiicient to withdraw the free end of the print hammer from between the type pallets even though the rotation of cam I3I may not have been suiiicient to begin the movement of bail I26 and bell crank I31 in clockwise direction. From the foregoing it will be observed that prlnting is accomplished by overtravel of'the print hammer as in the embodiment of the invention previously described. In the mechanism according to Fig. 2, however, only the print hammer I41 overtravels whereas in the embodiment shown in Fig. 1, the print hammer and the bell crank to which it is articulated overtravel.

Fig. 3 discloses a type wheel for the hereinbefore described printing telegraph receivin u it which may be'considered as an improvement on the type wheel disclosed and claimed in Patent No; 2,180,360 issued November 21, 1939, to Howard The type wheel is indicated generally by-the previously applied reference numeral 86 and its foundation is a cast or turned wheel which may comprise upper and lower flanges I6I; and I62, respectively; joined by in- :tesra dram po ti n I63.- Th nner su tia e of um po ien I63 i cyl nd cal and the externa um sur ac in l des a ridge 16.4 i tegral w th t d um por n I63 and l c te mi wa b tween t e l s I61 and IE2. Thef e of rid e I64 may b la n the s des the e fa e c ed toward the flanges I3] and 155 2, the inner fa es of which also curve to meet the curving sides of ridge I54 and form therewith spaced annular grooves of semicircular cross section. A plurality of radially directed type pallet slots is provided in the type wheel 86, the slots being cut entirely through the flange I62 and entirely through the drum portion I63 but only partially through the thickness of flange I6I.

Each of the slots in type wheel 86 receives and slidably supports the shanks I66 of two type pallets I61- The type pallet shanks I66 extend into the interior of type wheel 86 sufficiently far that they may be engaged and actuated by print hammer I41 (Fig. 2) or II4 (Fig. l) to effect printing. The type pallets I66 in the upper row have in their shanks I61 notches I68 which open downwardly and those in the lower row have similar notches I68 which open upwardly. A garter spring I69 extends through all of the notches I68 of the type pallets I51 in a row and biases them to their innermost positions radially of the type wheel. The annular ridge I64 which in cooperation with the inner faces of the flanges I6I and I62 defines peripheral grooves, separates the garter springs I69 and maintains them in the desired positions. When any type pallet I61 is reciprocated outwardly radially of the type wheel 86 by print hammer I41 or II4 the garter spring I69 which engages the shanks of the type pallets distends slightly, thus permitting the movement of the type pallet, and thereafter restores the type pallet to the innermost position.

The widths of the shanks of type pallets I61 are such that the lower edges of the shanks I66 of the lower row are substantially flush with the lower surface of flange I62 and the type pallets are retained in the slots in the type wheel 86 by a plate l1I which may be secured to flange I62 by a plurality of screws I12 threadedly engaging sectors of flange I62 between slots therein. Plate I1I may have a depressed central portion I13 which carries a locating pin I14 and has a plurality of apertures for clamping screws. The hub 84 slidable upon type wheel shaft 62 supports the depressed portion I13 of plate HI and is provided with a slot I16 which receives locating pin I14 and thereby establishes a predetermined angular relation between type wheel 86 and hub 84. Clamping screws I11 extend through the apertures in the depressed portion of plate HI and threadedly engage hub 84, thereby clamping type wheel 86 securely to the hub. Access to the screws I11 is had through the interior of wheel 86 from the top thereof.

Although specific embodiments of the features of the invention have been disclosed and described herein, it will be understood that the invention is not limited to such specific embodiments but is capable of modification, reorganization, rearrangement and substitution of parts are elements without departing from the spirit of the invention and within the scope of the appended claims.

What is claimed is:

1. In a type wheel for printing telegraph apparatus or the like, a pair of spaced flanges, a

drum portion interconnecting said flanges, a

periphera ride? inte ral ith said drum o tiqn d d intermed te sa d flanges, said dru portwn. rid e. a dfl nees ha i rad a l d posed sl t th ein. a p ura it ft pe e em arran e in rows and havi g shanks sl d ly disposed in said slots, the shanks of said type elementshavins notches therein, and a t r spri passing through the notches of all of the type ,elements in each row and biasing said type elements toward the center of said type wheel, said ridge and each adjacent flange forming a channel to maintain one of said garter springs in position in the notches of the associated row of type elements, the resiliency of each spring holding it in the channel thus formed.

2. In a type wheel for printing telegraph apparatus or the like, a pair of spaced flanges, a drum portion integral with said flanges, an anu d e ntegral with the drum portion on the external surface thereof, said drum portion, ridge, and flanges having slots therein radially of said type wheel, a pair of type elements having shanks slidably disposed in each of said slots, the shank of each type element in a slot having a notch opening toward the shank of the other type element, and a garter spring disposed between each of the flanges and the intermediate ridge and seated therebetween, each garter spring engaging the shanks of all of the the type elements in a row along the edge of the notch in the shank of each type element and biasing said type elements toward the axis of said type wheel.

3. In a type wheel for printing telegraph apparatus or the like, a pair of spaced flanges, a drum portion intermediate said flanges and integral with said flanges, the inner wall of each flange being joined to the periphery of said drum portion by an arcuate surface, a ridge integral with said drum portion and carried on the periphery thereof intermediate said flanges, the side walls of said ridge being joined to the peripheral surface of said drum portion by arcuate surfaces, said flanges, drum portion, and ridge having slots extending radially of said type wheel, type elements arranged around the periphery of said type wheel in rows, said type elements having shanks slidably disposed in said slots in pairs in superposed relation, the type element shanks in each slot having intercommunieating notches, and a garter spring seated upon the periphery of thedrum portion between each of the flanges and the intermediate ridge, each garter spring engaging an edge of the notch in each of the type element shanks of all of the type elements in a row and biasing said elements toward the axis of said type wheel.

4. In a type wheel for printing telegraph apparatus or the like, a pair of spaced flanges, a drum portion integral with said flanges and extending therebetween, said drum portion having a plurality of annular grooves in the periphery thereof, said flanges and drum portion having slots extending radially of said type wheel, type elements having shanks disposed in pairs in superposed relation in each of said slots, the shanks of a pair of type elements in a slot having intercommunicating notches, and a garter spring seating in each of said annular grooves in said drum portion and engaging the edges of the notches in the shanks of all of the type elements in a row and biasing said elements toward the center of said type wheel.

5. In a type wheel for printing telegraph apparatus or the like, a drum having outwardly extending flanges, a ridge intermediate said flanges and also extending outwardly from said drum, said flanges and ridge defining a pair of annular grooves extending around the drum, a plurality of slots formed in the drum and extending through one flange and part, Way through the other flange, a pair of annular rows of type pallets mounted on the drum and having shanks extending into said slots, the shanks of the type pallets of each of said rows having openings shaped to conform in part to the contour of one of said annular grooves, and a garter spring surrounding the drum and positioned in each of said grooves and in the openings in the shanks oi the type pallets of each of said rows to tend to hold the type pallets in their respective slots and to urge them radially inwardly.

CARL A. LEVIN. 

